Introduction: Enhanced expectations are a key factor of the OPTIMAL theory of motor learning, yet their effects on targeting skills under different experimental manipulations have not been sufficiently explored. This study aimed to investigate the effect of simultaneously observing both versions of the Ebbinghaus visual illusion on perception, motor learning, and self-efficacy in novice individuals.

Methods: This semi-experimental study was conducted using convenience sampling. Thirty-six male undergraduate participants were voluntarily and randomly assigned to the small-illusion perception group (M = 20.66) or the large-illusion perception group (M = 20.72). After familiarization with the task, a pretest (without the illusion) and dart-throwing practice (50 trials) were performed. Perception and self-efficacy were assessed before and after practice. In the retention test 48 hours later, perception, self-efficacy, and performance were measured.

Results: Learning was analyzed using a one-way ANOVA (pretest and retention), and practice-phase performance was examined using repeated-measures ANOVA. Target perception and self-efficacy were assessed using both one-way ANOVA and repeated-measures ANOVA. The findings indicated that the large perception group demonstrated better perception, higher self-efficacy, and superior performance during practice. However, no significant differences were observed between the groups in the retention test.

Conclusion: Simultaneous observation to the illusions can temporarily enhance motor performance; however, in the absence of the illusions, expectations and perception decline, leading to reduced performance accuracy. Future studies should incorporate extended practice with diverse samples and employ more precise measurements of motivational factors that may influence motor learning.